Blood Acetylcholinesterase Research Articles

Corylucinine, a new Alkaloid from Corydalis cava (Fumariaceae), and its Cholinesterase Activity

A new benzyldihydroisoquinoline alkaloid (1) was isolated from the tubers of Corydalis cava and named corylucinine. Additionally, 8-trichloromethyl-7,8-dihydropalmatine (2), an isolation artifact of tetrahydropalmatine, was obtained. The structures were established by spectroscopic (including 2D NMR and optical rotation) and HR-ESI-MS methods. Both compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibitory activity. In comparison with the used standards, both compounds showed only moderate inhibitory activity against HuAChE (IC50,. HuAChE = 127.6 +/- 5.2 microM for 1, and IC50, HuAChE = 82.9 +/- 3.9 microM for 2) and none against HuBuChE.

Protective effect of α-Tocopherol on memory deficits and Na+,K+-ATPase and acetylcholinesterase activities in rats with diet-induced hypercholesterolemia

BackgroundWe investigate behavioral tests, acetylcholinesterase (AChE) and Na+,K+-ATPase activities in rats with diet-induced hypercholesterolemia feeding and α-tocopherol administration. MethodsWe tested a protocol with four groups: standard diet (control); high-fat diet (HF); α-tocopherol (α-Toc); HF plus α-tocopherol (HF+α-Toc). HF was administered ad libitum and α-Toc (50mg/kg) by gavage. After three months of treatment we performed the behavioral tests. The biochemical assays were performed ex vivo in the cerebral cortex (CC), hippocampus (HP) and blood samples. ResultsThe behavioral tests results showed a decrease in step-down latency for the HF group (P<0.05). When rats that received HF were treated with α-toc (HF+α-Toc) the step-down latency was similar to the control group. AChE and Na+,K+-ATPase activities in homogenate and synaptosomes was observed a significant decrease in CC and HP in HF group (P<0.05). However, α-Toc group showed to reverse the decline in AChE and Na+,K+-ATPase activities in CC and HP. HF group showed a significant increase (P<0.05) in MDA levels in CC and HP in relation to other groups. However, α-Toc group showed a significant decrease (P<0.05) in MDA levels when only compared with the HF group. Blood AChE activity increased in α-Toc group (P<0.05) and decreased in HF group (P<0.05) compared to all groups. ConclusionsThe present outcomes showed that treatment with α-Toc prevents the inhibition of AChE and Na+,K+-ATPase activities and consequently memory impairment induced by HF diet, demonstrating that this compound can modulate cholinergic neurotransmission and consequently improve cognition in this experimental condition.

Evaluation of the Relationship Between Adenosine Deaminase, Myeloperoxidase, Cholinesterase, Preeclampsia Severity, and Neonatal Outcomes

We aimed to evaluate whole blood adenosine deaminase (ADA), myeloperoxidase (MPO), butyrylcholinesterase (BChE), and acetylcholinesterase (AChE) activities and to investigate whether there was a correlation between these enzymes and severity of preeclampsia and neonatal outcomes. Sixty-one pregnant women with mild (n = 31) or severe (n = 30) preeclampsia and 50 healthy controls were included in this study. Whole blood adenosine deaminase, myeloperoxidase, butyrylcholinesterase, and acetylcholinesterase activities were measured. Adenosine deaminase and myeloperoxidase activities were significantly higher in both mild and severe preeclamptic women than they were in the controls. There was also a significant difference between the severe and the mild preeclamptic groups with respect to these enzyme activities. Although BChE activity was lower in the severe preeclamptic women than it was in the healthy controls (P < .05), AChE activity was similar in all groups (P > .05). We noted an inverse correlation between ADA activity and birth weight (r = −0.337) (P < .05) and between MPO activity and Apgar scores at 1 and 5 minutes (r = −0.438 and r = −0.475, respectively, P < .01). We concluded that elevated ADA and MPO but not AChE activities may correlate with disease severity and neonatal outcomes in preeclamptic women. Further studies are needed to elucidate the exact roles of ADA and MPO in the pathophysiology of preeclampsia.

Complete blood count and acetylcholinesterase activity of lymphocytes of demyelinated and ovariectomized rats treated with resveratrol

Resveratrol is a phytoestrogen that has many beneficial actions. This study aimed to evaluate the effect of resveratrol on the complete blood count (CBC) and the acetylcholinesterase (AChE) activity of lymphocytes of ovariectomized rats experimentally demyelinated by ethidium bromide (EB). Forty adult female Wistar rats (60 days, 200–220 g) were divided randomly into five groups (n = 4) to evaluate the demyelination phase and five groups (n = 4) to evaluate the remyelination phase. In each phase, the groups consisted of sham rats–G1; ovariectomized rats, not demyelinated, treated only with vehicle (ethanol 25%)–G2; demyelinated ovariectomized rats treated only with vehicle–G3; ovariectomized rats, not demyelinated, treated with resveratrol–G4; and demyelinated ovariectomized rats treated with resveratrol–G5. Only during the remyelination phase, CBC showed a significant difference (p < 0.05) in the number of monocytes between G2 and G5 groups. In the demyelination phase, there was a significant decrease (p < 0.05) in the AChE activity in the G4 group, while the G5 group was statistically similar to the G1, G2 and G4 groups. In the remyelination phase, there were no significant differences in the AChE activity among the groups. The treatment for 7 days with resveratrol with or without the experimental demyelization with EB appears to influence the AChE activity of lymphocytes, without changing the number of these cells in the circulation. However, in the remyelination phase, there seems to be stabilization in its effect on the lymphocyte AChE activity.

Effects of the organophosphate fenthion for control of the red-billed quelea Quelea quelea on cholinesterase and haemoglobin concentrations in the blood of target and non-target birds

The red-billed quelea bird Quelea quelea is one of sub-Saharan Africa's most damaging pests, attacking small-grain crops throughout semi-arid zones. It is routinely controlled by spraying its breeding colonies and roosts with organophosphate pesticides, actions often associated with detrimental effects on non-target organisms. Attributions of mortality and morbidity of non-targets to the sprays are difficult to confirm unequivocally but can be achieved by assessing depressions in cholinesterase activities since these are reduced by exposure to organophosphates. Here we report on surveys of birds caught before and after sprays that were examined for their blood cholinesterase activities to assess the extent to which these became depressed. Blood samples from birds were taken before and after sprays with fenthion against red-billed quelea in colonies or roosts, and at other unsprayed sites, in Botswana and Tanzania and analysed for levels of haemoglobin (Hb) and activities of whole blood acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Background activities of AChE, BChE and Hb concentrations varied with bird species, subspecies, mass, age and gender. Contrary to expectation, since avian erythrocytes are often reported to lack cholinesterases, acetylcholinesterase activities in pre-spray samples of adult birds were positively correlated with Hb concentrations. When these factors were taken into account there were highly significant declines (P < 0.0001) in AChE and BChE and increases in Hb after contact with fenthion in both target and non-target birds. BChE generally declined further (up to 87 % depression) from baseline levels than AChE (up to 83 % depression) but did so at a slower rate in a sample of quelea nestlings. Baseline activities of AChE and BChE and levels of Hb were higher in the East African subspecies of the red-billed quelea Q. q. aethiopica than in the southern African subspecies Q. q. lathamii, with the exception of BChE activities for adult males which were equivalent.

Development and validation of a simple assay for the determination of cholinesterase activity in whole blood of laboratory animals

Current methods for measuring acetylcholinesterase (AChE) activities in whole blood use butyrylcholinesterase (BChE)-selective inhibitors. However, the poor selectivity of these inhibitors results in the inhibition of AChE activity to some degree, leading to errors in reported values. The goal of this study was to develop and validate a simple assay for measuring AChE and BChE activities in whole blood from humans as well as experimental animals. Blood was fractionated into plasma and erythrocytes, and cholinesterase activities were titrated against ethopropazine and (-)-huperzine A to determine the lowest concentration of ethopropazine that inhibited BChE completely without affecting AChE activity and the lowest concentration of (-)-huperzine A that inhibited AChE completely without interfering with BChE activity. Results indicate that 20 µm ethopropazine can be successfully used for the accurate measurement of AChE activity in blood from humans as well as animals. Use of (-)-huperzine A is not required for measuring BChE activity in normal or 'exposed' blood samples. The method was validated for blood from several animal species, including mice, rats, guinea pigs, dogs, minipigs, and African green, cynomolgus and rhesus monkeys. This method is superior to all reported methods, does not require the separation of erythrocyte and plasma fractions, and is suitable for measuring cholinesterase activities in fresh or frozen blood from animals that were exposed to nerve agents or those that were administered high doses of BChE. The method is simple, direct, reproducible, and reliable and can easily be adapted for high-throughput screening of blood samples. Published 2012. This article is a US Government work and is in the public domain in the USA.

A role for solvents in the toxicity of agricultural organophosphorus pesticides

Organophosphorus (OP) insecticide self-poisoning is responsible for about one-quarter of global suicides. Treatment focuses on the fact that OP compounds inhibit acetylcholinesterase (AChE); however, AChE-reactivating drugs do not benefit poisoned humans. We therefore studied the role of solvent coformulants in OP toxicity in a novel minipig model of agricultural OP poisoning. Gottingen minipigs were orally poisoned with clinically relevant doses of agricultural emulsifiable concentrate (EC) dimethoate, dimethoate active ingredient (AI) alone, or solvents. Cardiorespiratory physiology and neuromuscular (NMJ) function, blood AChE activity, and arterial lactate concentration were monitored for 12h to assess poisoning severity. Poisoning with agricultural dimethoate EC40, but not saline, caused respiratory arrest within 30min, severe distributive shock and NMJ dysfunction, that was similar to human poisoning. Mean arterial lactate rose to 15.6 [SD 2.8] mM in poisoned pigs compared to 1.4 [0.4] in controls. Moderate toxicity resulted from poisoning with dimethoate AI alone, or the major solvent cyclohexanone. Combining dimethoate with cyclohexanone reproduced severe poisoning characteristic of agricultural dimethoate EC poisoning. A formulation without cyclohexanone showed less mammalian toxicity. These results indicate that solvents play a crucial role in dimethoate toxicity. Regulatory assessment of pesticide toxicity should include solvents as well as the AIs which currently dominate the assessment. Reformulation of OP insecticides to ensure that the agricultural product has lower mammalian toxicity could result in fewer deaths after suicidal ingestion and rapidly reduce global suicide rates.

The Ability of Oxime Mixtures to Increase the Reactivating and Therapeutic Efficacy of Antidotal Treatment of Cyclosarin Poisoning in Rats and Mice

The reactivating and therapeutic efficacy of two combinations ofoximes (HI-6 + trimedoxime and HI-6 + K203) was compared with the effectiveness of antidotal treatment involving single oxime (HI-6, trimedoxime, K203) using in vivo methods. In vivo determined percentage of reactivation of cyclosarin-inhibited blood and tissue acetylcholinesterase in poisoned rats showed that the reactivating efficacy of both combinations of oximes is slightly higher than the reactivating efficacy of the most effective individual oxime in blood, diaphragm as well as in brain. Moreover, both combinations of oximes were found to be slightly more efficacious in the reduction of acute lethal toxic effects in cyclosarin-poisoned mice than the antidotal treatment involving single oxime. Based on the obtained data, we can conclude that the antidotal treatment involving chosen combinations of oximes brings a beneficial effect for its ability to counteract the acute poisoning with cyclosarin.

Cholinesterase activities and biochemical determinations in patients with prostate cancer: Influence of Gleason score, treatment and bone metastasis

Prostate cancer (PCa) is the sixth most common type of cancer worldwide. Cholinesterase is well known as having non-cholinergic functions such as cellular proliferation and differentiation, suggesting a possible influence of cholinesterase in tumorogenesis. Thus, the aim of this study was to investigate the whole blood acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BChE) activities and some biochemical parameters in PCa patients. This study was performed in 66 PCa patients and 40 control subjects. AChE and BChE activities were determined in PCa patients and the influence of the Gleason score; bone metastasis and treatment in the enzyme activities were also verified. Furthermore, we also analyzed possible biochemical alterations in these patients. AChE and BChE activities decreased in PCa patients in relation to the control group and various biochemical changes were observed in these patients. Moreover, Gleason score, metastasis and treatment influenced cholinesterase activities and biochemical determinations. Our results suggest that cholinesterases activities and biochemical parameters are altered in PCa. These facts support the idea that the drop in the cholinesterase activity and the consequent increased amount of acetylcholine could lead to a cholinergic overstimulation and increase the cell proliferation in PCa.

Isolation and Cholinesterase Activity of Amaryllidaceae Alkaloids from Nerine bowdenii

Amaryllidaceae species are known as ornamental plants. Some contain galanthamine, an acetylcholinesterase inhibitor. The chemical composition of the alkaloid extract of bulbs of Nerine bowdenii Watson has been analyzed by means of GC/MS. Twenty-two compounds were detected and nineteen of them identified, one of which was belladine. The alkaloid extract showed promising cholinesterase inhibitory activities against human blood acetylcholinesterase (HuAChE; IC50 = 87.9 +/- 3.5 microg/mL) and human plasma butyrylcholinesterase (HuBuChE; IC50 = 14.8 +/- 1.1 microg/mL). Belladine inhibited HuAChE and HuBuChE in a dose-dependent manner with IC50 values of 781 +/- 12.5 microM and 284.8 +/-4.2 microM, respectively.

Acrylonitrile has Distinct Hormetic Effects on Acetylcholinesterase Activity in Mouse Brain and Blood that are Modulated by Ethanol

Acrylonitrile(AN) is a neurotoxin both in animals and humans, but its effects on acetylcholinesterase (AChE) activity remain controversial. This study aimed to determine the dose-response effects of AN on AChE activity and the modulatory role of ethanol pre-treatment. A total of 144 Kunming mice were randomly divided into 18 groups: nine groups received 5% ethanol in their drinking water, and the remaining nine groups received regular tap water. One week later, both the ethanol and tap water only groups were given an intraperitoneal injection of AN at the following doses: 0 (control), 0.156, 0.3125, 0.625, 1.25, 2.5, 5, 10 or 20 mg AN/kg body weight. AChE activity was determined on whole blood and brain 24 h later. Blood AChE activity was higher in AN-injected mice than in controls at all doses. AChE activity in blood increased in a dose-dependent manner, peaking at 0.156 mg/kg, after which a gradual decrease ensued, displaying a β-typed dose-response relationship. In contrast, brain AChE activity, following a single AN injection, was consistently lower than in control mice, and continued to fall up to a dose of 0.313 mg/kg, and thereafter increased gradually with higher doses. Mice receiving a 20 mg/kg dose of AN exhibited AChE brain activity indistinguishable from that of control mice, demonstrating a typical U-typed dose-response relationship. The activity of AChE in the blood and brain of the AN + ethanol-treated groups displayed a shift to the right, and the magnitude of the decrease in AChE activity induced by AN was attenuated relative to the AN-only group. These results suggest that AN affects AChE activity in both mouse blood and brain in a hormetic manner. Pretreatment with ethanol modifies the effect of AN on AChE, indicating that parent AN has a more prominent role than its metabolites in modulating enzyme activity.

Mutagenic, genotoxic and enzyme inhibitory effects of carbosulfan in rainbow trout Oncorhynchus mykiss

Rainbow trout ( Oncorhynchus mykiss; 116.88 ± 21.69 g) were exposed to sublethal concentrations (25 μg/L) of carbosulfan for 60 days to test if the long term exposure of fish to carbosulfan affects red blood cells acetylcholinesterase (AChE), δ-aminolevulinic acid dehydratase (ALA-D) and paraoxonase (PON) enzyme activity and induces genotoxic and/or mutagenic effects. The exposure resulted in inhibition of AChE and ALA-D activity of rainbow trout when compared to control fish. The activity of PON was not affected by carbosulfan. Interestingly, carbosulfan was found to induce DNA damage in red blood cells (comet assay) and proved to be mutagenic as revealed by the Ames test. Results indicate that blood AChE and ALA-D of rainbow trout may be a sensitive biomarker for assessment of carbosulfan contaminated water bodies. Furthermore, because the Ames test and comet assay were proven successful to detect the genotoxicity of carbosulfan, we proposed that nonlethal techniques such as blood collection from caudal vein of fish should be used to determine potential toxic effects of other pesticides to surrounding environment.

Comparative Analysis of Esterase Activities of Human, Mouse, and Rat Blood

Acetylcholinesterase, butyrylcholinesterase, carboxylesterase, and paraoxonase activities in human, mouse, and rat blood were measured. The proportions of these enzymes activities differed significantly. In humans, the most significant were cholinesterase activities, while in rats and mice the contribution of carboxylesterase activity was the greatest. High arylesterase activity of paraoxonase was observed in all cases. Species-specific differences should be taken into consideration when carrying out preclinical trials on rodents for optimization of the pharmacokinetic characteristics of drugs containing complex ester groups.

Cholinesterases as markers of the inflammatory process in rats infected with Leptospira interrogans serovar Icterohaemorrhagiae

The aim of this study was evaluate changes in the cholinesterase activity in blood, lymphocytes and serum of rats infected with Leptospira interrogans serovar Icterohaemorrhagiae ('L. icterohaemorrhagiae'). Sixty adult Wistar rats were divided into six groups of 10 animals: three control groups and three test groups. The animals from the test groups were intraperitoneally inoculated with 1 ml medium containing 1 × 10(8) leptospires. The activity of acetylcholinesterase in blood and butyrylcholinesterase in serum increased on days 5 (P<0.05) and 30 (P<0.021) post-infection, respectively. A decrease in lymphocyte count was observed on days 15 (P<0.01) and 30 post-infection (P<0.05). On day 15 post-infection, acetylcholinesterase activity (P<0.001) in lymphocytes decreased in infected rats. However, on day 30 post-infection there was an increase in acetylcholinesterase activity in lymphocytes. In conclusion, our results showed that the activity of enzymes of the cholinergic system in the total blood, lymphocytes and serum is altered as a result of inflammation caused by infection with L. icterohaemorrhagiae. The possible causes of these alterations will be discussed in this paper.

+]-Huperzine A Protects Against Soman Toxicity in Guinea Pigs

The chemical warfare nerve agent (CWNA) soman irreversibly inhibits acetylcholinesterase (AChE) causing seizure, neuropathology and neurobehavioral deficits. Pyridostigmine bromide (PB), the currently approved pretreatment for soman, is a reversible AChE inhibitor that does not cross the blood-brain barrier (BBB) to protect against central nervous system damage. [-]-Huperzine A, a natural reversible AChE inhibitor, rapidly passes through the BBB and has numerous neuroprotective properties that are beneficial for protection against soman. However, [-]-Huperzine A is toxic at higher doses due to potent AChE inhibition which limits the utilization of its neuroprotective properties. [+]-Huperzine A, a synthetic stereoisomer of [-]-Huperzine A and a weak inhibitor of AChE, is non-toxic. In this study, we evaluated the efficacy of [+]-Huperzine A for protection against soman toxicity in guinea pigs. Pretreatments with [+]-Huperzine A, i.m., significantly increased the survival rate in a dose-dependent manner against 1.2× LD(50) soman exposures. Behavioral signs of soman toxicity were significantly reduced in 20 and 40 mg/kg [+]-Huperzine A treated animals at 4 and 24 h compared to vehicle and PB controls. Electroencephalogram (EEG) power spectral analysis showed that [+]-Huperzine A significantly reduces soman-induced seizure compared to PB. [+]-Huperzine A (40 mg/kg) preserved higher blood and brain AChE activity compared to PB in soman exposed animals. These data suggest that [+]-Huperzine A protects against soman toxicity stronger than PB and warrant further development as a potent medical countermeasure against CWNA poisoning.

Analysis of Amaryllidaceae alkaloids from Zephyranthes grandiflora by GC/MS and their cholinesterase activity

Amaryllidaceae are known as ornamental plants, furthermore some species of this family contain galanthamine, an acetylcholinesterase inhibitor approved for the treatment of Alzheimer's disease, and other alkaloids with interesting pharmacological activity. The chemical composition of alkaloids from Zephyranthes grandiflora Lindl. was analyzed by GC/MS. Seven known compounds, belonging to five structural types of Amaryllidaceae alkaloids, were identified. The alkaloid extract from the bulbs showed promising cholinesterase inhibitory activities against human blood acetylcholinesterase (HuAChE; IC50 39.2±3.0 µg/mL) and human plasma butyrylcholinesterase (HuBuChE; IC50 356±9.3 µg/mL).

In vitro detoxification of cyclosarin in human blood pre-incubated ex vivo with recombinant serum paraoxonases

An ex vivo protocol was developed to assay the antidotal capacity of rePON1 variants to protect endogenous acetylcholinesterase and butyrylcholinesterase in human whole blood against OP nerve agents. This protocol permitted us to address the relationship between blood rePON1 concentrations, their kinetic parameters, and the level of protection conferred by rePON1 on the cholinesterases in human blood, following a challenge with cyclosarin (GF). The experimental data thus obtained were in good agreement with the predicted percent residual activities of blood cholinesterases calculated on the basis of the rate constants for inhibition of human acetylcholinesterase and butyrylcholinesterase by GF, the concentration of the particular rePON1 variant, and its k cat/ K m value for GF. This protocol thus provides a rapid and reliable ex vivo screening tool for identification of rePON1 bioscavenger candidates suitable for protection of humans against organophosphorus-based toxicants. The results also permitted the refinement of a mathematical model for estimating the efficacious dose of rePON1s variants required for prophylaxis in humans.

Effects of K074 and pralidoxime on antioxidant and acetylcholinesterase response in malathion-poisoned mice

The organophosphorus (OP) pesticide malathion is a highly neurotoxic compound and its toxicity is primarily caused by the inhibition of acetylcholinesterase (AChE), leading to cholinergic syndrome. Although oximes have been used as potential antidotal treatments in malathion poisoning because of their potential capability to reactivate the inhibited enzyme, the clinical experience with the clinically available oximes (e.g. pralidoxime) is disappointing and their routine use has been questioned. In the present study, we investigated the potency of pralidoxime and K074 in reactivating AChE after acute exposure to malathion, as well as in preventing malathion-induced changes in oxidative-stress related parameters in mice. Malathion (1.25g/kg, s.c.) induced a significant decrease in cortico-cerebral, hippocampal and blood AChE activities at 24h after exposure. Oxime treatments (1/4 of LD50, i.m., 6h after malathion poisoning) showed that pralidoxime significantly reversed malathion-induced blood AChE inhibition, although no significant effects were observed after K074 treatment. Interestingly, both oximes tested were unable to reactivate the cortico-cerebral and hippocampal enzymes after intramuscular or intracerebroventricular injection (1/4 of LD50, 6h after malathion poisoning). Biochemical parameters related to oxidative stress (cerebro-cortical and hippocampal glutathione peroxidase, glutathione reductase and catalase activities, as well as lipid peroxidation) were not affected in animals treated with malathion, oximes or atropine alone. However, pralidoxime and K074, administered intramuscularly 6h after malathion poisoning, were able to increase the endogenous activities of these antioxidant enzymes in the prefrontal cortex and hippocampus. Taken together, the results presented herein showed that pralidoxime (the most common clinically used oxime) and the recently developed oxime K074, administered 6h after malathion poisoning, were unable to reactivate the inhibited AChE in mouse prefrontal cortex and hippocampus. However, only pralidoxime significantly reversed the blood AChE inhibition induced by malathion poisoning. This indicates that peripheral and central AChE activities are not necessarily correlated after the treatment of OP compounds and/or oximes, which should be taken into account in the diagnosis and management of OP-exposed humans. In addition, considering that the available treatments to malathion poisoning appear to be ineffective, the present study reinforce the need to search for potential new AChE reactivators able to efficiently reactivate the brain and blood AChEs after malathion poisoning.

Acetylcholinesterase and Butyrylcholinesterase Inhibitory Compounds from Corydalis Cava (Fumariaceae)

Tubers of Corydalis cava were extracted with ethanol and fractionated using n-hexane, chloroform and ethanol. Repeated column chromatography, preparative TLC and crystallization led to the isolation of fifteen isoquinoline alkaloids. The chemical structures of the isolated compounds were determined on the basis of spectroscopic techniques and by comparison with literature data. All isolated compounds were tested for human blood acetylcholinesterase (HuAChE) and human plasma butyrylcholinesterase (HuBuChE) inhibitory activity. (+)-Canadaline inhibited acetylcholinesterase as well as butyrylcholinesterase in a dose-dependent manner with IC50 values of 20.1 +/- 1.1 microM and 85.2 +/- 3.2 microM, respectively. (+)-Canadine, with an IC50 value of 12.4 +/- 0.9 microM, was the most potent inhibitor of acetylcholinesterase, whilst (+/-)-corycavidine and (+)-bulbocapnine were effective inhibitors of butyrylcholinesterase with IC50 values of 46.2 +/- 2.4 microM and 67.0 +/- 2.1 microM, respectively. The other isolated alkaloids were considered inactive (IC50 > 100 microM).

Analysis of Amaryllidaceae Alkaloids from Chlidanthus Fragrans by GC-MS and their Cholinesterase Activity

The underivatized alkaloid mixture extracted from the bulbs of Chlidanthus fragrans Herb. was investigated by capillary GC/MS for the first time. Fifteen known Amaryllidaceae alkaloids of five structure types were identified. The main alkaloids were tazzetine (9, tazettine-type), chlidanthine (2, galanthamine-type), belladine (8, belladine-type) and lycorine (12, lycorine-type). The alkaloid extract from the bulbs showed promising human blood acetylcholinesterase (IC50 = 20.1 +/- 2.9 microg/mL) and human plasma butyrylcholinesterase (IC50 = 136.8 +/- 6.9 microg/mL) inhibitory activity.